Welder Output Voltage: CC vs CV Explained

What CC and CV mean on a welder listing

Welder titles rarely write out “constant current” or “constant voltage.” Instead, the listed processes tell you. A machine titled as a stick welder, a TIG welder, or a stick/TIG combo uses constant current output. A machine titled as a MIG welder or a flux core welder uses constant voltage output. A multi-process welder that lists both stick and MIG on the title switches between CC and CV modes, and the listing often names the modes in the spec table. For a list of machines that offer both modes, see the best multi-process welders guide.

The output voltage characteristic is not a feature you adjust on the machine. It is a design property of the power source. The maker builds the internal circuitry to deliver a CC or CV output arc, and on a multi-process machine a selector switch or a digital menu chooses the mode.

Constant current: stick and TIG

In constant current output, the welder keeps the amperage near the set value even when the arc length changes. When you hold a stick electrode closer to the work, the voltage drops but the current stays close to the dial setting. This self-regulating behavior lets the welder maintain a steady arc as your hand moves during stick welding or as you add filler rod while TIG welding.

Stick welding (SMAW) and TIG welding (GTAW) both use CC output. The American Welding Society specifies these processes as constant current because the welder controls arc length by hand and needs a consistent melting rate. If a stick welder used CV output, the amperage would rise sharply when the arc shortened and the electrode would dig in or stick. For more on choosing a stick welder, see the best stick welders guide; for TIG, see the best TIG welders guide.

If you see a title like “Stick Welder 160A” or “DC TIG Stick Combo,” the machine is a CC power source. A dedicated stick or TIG welder cannot run a MIG wire feeder because MIG requires a CV power source.

• CC output holds current steady; voltage changes with arc length.
• Used by stick (SMAW) and TIG (GTAW) welders.
• No wire feeder needed. The electrode itself is the filler.

Constant voltage: MIG and flux core

In constant voltage output, the welder keeps the voltage near the set value while the current changes with the wire feed speed. When the wire touches the work, the voltage drops and the welder increases current to melt the wire at a rate matched to the feed speed. This self-regulating wire burnoff is what makes MIG welding easy: the machine automatically adjusts current to keep a stable arc as the wire feeds.

MIG welding (GMAW) and flux core welding (FCAW) both use CV output. The wire feed speed controls the amperage, so a MIG welder without a built-in wire feeder cannot produce a CC arc. If you connect a MIG gun to a CC stick welder, the arc becomes unstable and the wire tends to jam or burn back. For picking a MIG welder, the best MIG welders guide compares models on stated details.

A listing titled “MIG Welder 200A” or “Flux Core Welder 125A” is a CV power source. Some multi-process titles say “MIG/TIG/Stick” to tell you the machine offers both CV and CC modes. The best multi-process welders guide covers those machines.

• CV output holds voltage steady; current varies with wire feed speed.
• Used by MIG (GMAW) and flux core (FCAW) welders.
• A built-in wire feeder is part of the machine.

Multi-process machines: switching between CC and CV

A multi-process welder that lists MIG, TIG and stick on the title contains a power source that can operate in either CC or CV mode. The maker provides a switch, a digital menu or an automatic process selection that changes the output characteristic when you change the process. When you select stick or TIG, the machine sets CC output. When you select MIG or flux core, the machine sets CV output.

This built-in switching is why a single multi-process machine can handle all three common processes. The best multi-process welders guide lists models that include both CC and CV modes. A multi-process welder without a MIG process (a stick/TIG combo) is CC-only and cannot run a MIG wire feeder.

If you plan to buy one machine for stick and MIG work, confirm the title or spec sheet lists both processes. That tells you the power source includes both CC and CV modes.

Why output characteristic matters when you buy

The output voltage characteristic determines what you can weld and how easy the machine is to use for each job. If you already own tools that expect one characteristic, choosing a machine with the wrong output will keep you from using those tools.

If you want to use a MIG wire feeder or a spool gun, the power source must supply CV output. A CC-only stick welder cannot drive a MIG gun regardless of the amperage. If you want to use a foot pedal with TIG, the machine must be in CC mode. For a machine that runs both CC and CV, see the best multi-process welders guide. If you need a portable CC machine for repairs, the best dual voltage welders guide may help.

The output characteristic also affects how a welder responds to your skill level. A CV MIG welder is easier for a first user because the machine self-regulates the arc length. A CC stick welder requires the user to hold a steady arc length by hand. If you are choosing a first machine, the process list on the title tells you which characteristic you will be using. The best welder guide offers an overview of all process types.

• A CC-only machine (stick/TIG) cannot drive a MIG wire feeder.
• A CV-only machine (MIG/flux core) cannot run stick or TIG without a CC mode.
• Multi-process machines with MIG, TIG and stick include both CC and CV modes.
• The characteristic is not adjustable; it is built into the machine.

What to pick for your situation

Questions

Can a MIG welder work for stick welding?

No, because a MIG welder outputs constant voltage (CV). Stick welding requires constant current (CC) output. Some multi-process welders include both CV and CC modes, so one machine can do MIG and stick switching modes.

Does a TIG welder use constant current or constant voltage?

TIG welders use constant current (CC) output. The welder sets the amperage and the arc length is controlled by the welder’s hand. This matches the CC characteristic.

What does “CV” stand for on a welder spec sheet?

CV stands for constant voltage. A CV power source holds the voltage steady while the current varies with wire feed speed. It is used for MIG and flux core welding.

Do I need a special machine for flux core welding?

Flux core welding uses constant voltage output, just like MIG. A MIG welder or a multi-process welder in MIG mode runs flux core wire. A CC-only stick or TIG welder cannot run flux core wire.

How do I know if a welder is CC or CV from the title?

Read the list of processes. If the title says “MIG” or “Flux Core,” it is CV. If the title says “Stick” or “TIG” alone, it is CC. A title that names both MIG and stick means the machine has both modes.

Can a CC welder be used with a spool gun for aluminum?

No, a spool gun requires constant voltage output from the power source. A CC-only stick or TIG welder cannot drive a spool gun. You need a MIG welder (CV) or a multi-process welder in MIG mode.